Preheat oven to 375. For the EASY PIE CRUST, whip oil and milk together with a fork. Add in the flour, sugar, and salt and mix with a fork until well blended.
Press into the pan. Bake 12-15 minutes. Cool.
FOR THE FILLING, in a large heavy saucepan, mix sugar and cornstarch. Whisk in milk and lemon juice until smooth. Cook and stir over medium-high heat until thickened and bubbly. Reduce heat to low; cook and stir 2 minutes longer. Remove from heat.
In a small bowl, whisk a small amount of hot mixture into egg yolks; return all to the pan, whisking constantly. Bring to a gentle boil; cook and stir 2 minutes. Remove from heat. Stir in butter and lemon peel. Cool without stirring
Stir in sour cream. Add filling to crust. Top with whipped cream (or serve separatley) and fresh lemon zest. Store in the refrigerator.